Merge branch 'add-gon-jira-connect-app' into 'master'

Add gon to Jira Connect App

See merge request gitlab-org/gitlab!48865

app/views/layouts/jira_connect.html.haml

@@ -9,6 +9,7 @@
 
     = javascript_include_tag 'https://connect-cdn.atl-paas.net/all.js'
     = javascript_include_tag 'https://unpkg.com/jquery@3.3.1/dist/jquery.min.js'
+    = Gon::Base.render_data(nonce: content_security_policy_nonce)
     = yield :head
   %body
     .ac-content